在将输入类型=“文件”上传的数据插入到postgres数据库之前，如何将其转换为blob格式？

Question

我有一个页面可以将文件上传到服务器。现在，由于我将文件存储在数据库中的类型为（bytea）的列中，因此我想知道如何在通过axios发送文件之前将该文件转换为blob数据.post。

FileUpload.vue

class ReturnProductInvoiceForm(ModelForm):
    invoice_number = ModelChoiceField(queryset=InvoiceModel.objects.all())
    class Meta:
       model = ReturnInvoiceModel
       fields = ['invoice_number']

class ReturnProductQuantityForm(ModelForm):
    product = ModelChoiceField(queryset=Products.objects.all())
    class Meta:
       model = SelectQuantityReturnModel
       fields = ['product','quantity','price']
    def clean(self):
        #i need to clean the form right here 
        #if invoice_number in `ReturnProductInvoiceForm` has not `product` then raise some error!

class TestClass
{
    TestClass([string]$msg) {
        Write-Host "Ctor sees: $msg"
    }
    TestMethod([string]$msg) {
        Write-Host "TestMethod sees: $msg"
    }
}

# this works:
$x = Get-Date
$test1 = [TestClass]::new($x)

# this also works:
$x = Get-Date
$test1.TestMethod($x)

# but doing the same thing inline is a syntax error: Missing ')' in method call.
$test2 = [TestClass]::new(Get-Date)
$test2 = [TestClass]::new(Get-Date())
$test1.TestMethod(Get-Date)

读取数组缓冲区并将其转换为二进制字符串

<template>
<div class="file">
<input type="file"  @change="Images_onFileChanged">  
</div>
</template>
<script>
export default {
  name: 'FileUpload',
  data () {
    return {
      selectedFile : null
    }
  },
  methods: {
      Images_onFileChanged (event) {
          console.log('inside Images_onFileChanged '+event.target.files[0]); 
          console.log('inside Images_onFileChanged  seassion id is'+this.$store.getters.getSessionData().key);    
          var sessionid= this.$store.getters.getSessionData().key; 
          var chosenfile=this.selectedFile = event.target.files[0];
          this.$store.dispatch('uploadFile',{chosenfile,sessionid} ); 
    
        }

}
}
</script>

使用当前代码后操作成功，但是在数据库中blob列值显示为null（请参见屏幕截图）。请帮助？我在这里做什么错了？

注意：将存储Blob的列类型为（bytea）类型。